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Publication numberUS6544373 B2
Publication typeGrant
Application numberUS 09/682,137
Publication dateApr 8, 2003
Filing dateJul 26, 2001
Priority dateJul 26, 2001
Fee statusPaid
Also published asCN1400636A, US20030019570
Publication number09682137, 682137, US 6544373 B2, US 6544373B2, US-B2-6544373, US6544373 B2, US6544373B2
InventorsHsueh-Chung Chen, Teng-Chun Tsai
Original AssigneeUnited Microelectronics Corp.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Polishing pad for a chemical mechanical polishing process
US 6544373 B2
Abstract
The present invention gives a method of fabricating a composite polishing pad. A first polishing pad has a glue layer on a surface of the first polishing pad and a number of hard polishing materials positioned on the glue layer. Then portions of the first polishing pad are punched off to remove portions of the hard polishing material positioned on the surface of the first polishing pad so as to form holes penetrating the first polishing pad. A second polishing pad has a glue layer on a surface of the second polishing pad, and soft polishing materials adhere to the glue layer. Then portions of the soft polishing material positioned on the surface of the second polishing pad are removed while retaining the glue layer, and the portions of the soft polishing material retained on the surface of the second polishing pad completely match the holes formed in the first polishing pad. Finally, the first polishing pad is stuck on the surface of the second polishing pad so as to form a composite polishing pad having a pattern formed by the hard and soft polishing materials on the surface of the composite polishing pad.
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Claims(12)
What is claimed is:
1. A method of fabricating a composite polishing pad, the method comprising:
providing a first polishing pad which comprises a glue layer on a surface of the first polishing pad and a plurality of hard polishing materials positioned on the glue layer;
removing portions of the first polishing pad to remove portions of the hard polishing material positioned on the surface of the first polishing pad so as to form a plurality of holes penetrating the first polishing pad;
providing a second polishing pad which comprises a glue layer on a surface of the second polishing pad and a plurality of soft polishing materials adhering to the glue layer;
removing portions of the soft polishing material positioned on the surface of the second polishing pad while retaining the glue layer, and the soft polishing material retained on the surface of the second polishing pad completely matching the holes formed in the first polishing pad; and
sticking the first polishing pad on the surface of the second polishing pad so as to form a composite polishing pad;
wherein the surface of the composite polishing pad comprises a pattern formed by the hard and soft polishing materials.
2. The method of claim 1 wherein the pattern on the surface of the composite polishing pad is formed by interlacing the hard and soft polishing materials along an X-axis and Y-axis of the surface of the composite polishing pad.
3. The method of claim 1 wherein the pattern on a surface of the composite polishing pad is formed by respectively arranging hard and soft polishing materials as rings in concentric circles with different radiuses on the surface of the composite polishing pad.
4. The method of claim 1 wherein the pattern on the surface of the composite polishing pad is formed by interlacing hard and soft polishing materials along radial directions on the surface of the composite polishing pad.
5. The method of claim 1 wherein the area ratio of hard and soft polishing materials positioned on the surface of the composite polishing pad is used to adjust removal rate and improve the uniformity of the surface of a semiconductor wafer after being polished.
6. A method of improving the polishing efficiency of a polishing pad, the method comprising:
providing a first polishing pad which comprises a glue layer on a surface of the first polishing pad and a plurality of first polishing materials positioned on the glue layer;
removing portions of the first polishing pad to remove portions of the first polishing material positioned on the surface of the first polishing pad so as to form a plurality of holes penetrating the first polishing pad;
providing a second polishing pad which comprises a glue layer on a surface of the first polishing pad and a plurality of second polishing materials adhering to the glue layer;
removing portions of the second polishing material positioned on the surface of the second polishing pad while retaining the glue layer, and the second polishing material retained on the surface of the second polishing pad matching the holes formed in the first polishing pad; and
sticking the first polishing pad on the surface of the second polishing pad so as to form a composite polishing pad;
wherein the surface of the composite polishing pad comprises a pattern formed by the first and second polishing material, so a composite polishing pad has both a good removal rate and polishing ability.
7. The method of claim 6 wherein the hardness of the first polishing material is greater than the hardness of the second polishinq material.
8. The method of claim 6 wherein the hardness of the second polishing material is greater than the hardness of the first polishing material.
9. The method of claim 6 wherein the pattern on the surface of the composite polishing pad is formed by interlacing the first and second polishing material along an X-axis and Y-axis of the surface of the composite polishing pad.
10. The method of claim 6 wherein the pattern on the surface of the composite polishing pad is formed by respectively arranging the first and second polishing materials as rings in concentric circles with different radiuses on a surface of the composite polishing pad.
11. The method of claim 6 wherein the pattern on the surface of the composite polishing pad is formed by interlacing the first and second polishing materials along radial directions of the surface of the composite polishing pad.
12. The method of claim 6 wherein the area ratio of the first and second polishing materials positioned on the surface of the composite polishing pad is used to adjust a removal rate and improve the uniformity of the surface of a semiconductor wafer after being polished.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of fabricating a composite polishing pad for a chemical mechanical polishing process.

2. Description of the Prior Art

Chemical mechanical polishing (CMP) is a method of polishing materials, such as a semiconductor wafer, to a high degree of planarity and uniformity. The process is used to planarize a semiconductor wafer prior to the fabrication of microelectronic circuitry thereon, and is also used to remove high-elevation features created during the fabrication of the microelectronic circuitry on the surface of the semiconductor wafer.

Please refer to FIG. 1. FIG. 1 is of a cross-sectional diagram of a semiconductor wafer 10. The semiconductor wafer 10 comprises a substrate 12, a conductive layer 14 positioned on the surface of the substrate 12 and a dielectric layer 16 positioned on the surface of the substrate 12. The dielectric layer 16 covers the conductive layer 14. Please refer to FIG. 2. FIG. 2 is of a perspective view of a chemical mechanical polishing apparatus 20. The chemical mechanical polishing apparatus 20 comprises a polishing table 22, a polishing pad 24 set on the polishing table 22, a holder 28 for pressing the semiconductor wafer 10 onto the polishing pad 24, a slurry supply apparatus 30 for supplying a slurry to polish the semiconductor wafer 10, and a conditioner 32 to control the distribution of the slurry on the polishing pad and to remove polished material that is formed during the polishing process.

Please refer to FIG. 3 and FIG. 4. FIG. 3 is a top view of the polishing pad 24, and FIG. 4 is a cross-sectional diagram of the polishing pad according to the prior art. The polishing pad 24 comprises three concentric circular grooves 26. The slurry drops from the slurry supply apparatus 30 to the surface of the polishing pad 24 and flows along the concentric circular grooves 26 so as to distribute the slurry over the surface of the polishing pad.

According to the prior art, the semiconductor wafer 10 is set in the holder 28 before performing the chemical mechanical polishing process. The back surface of the semiconductor wafer 10 is held by the holder 28 and the front surface of the semiconductor wafer 10 is pressed onto the surface of the polishing pad 24. During the chemical mechanical polishing process, the holder 28 rotates counterclockwise and moves to-and-fro, and the polishing table 22 also rotates counterclockwise. The relative motion of the semiconductor wafer 10 with the polishing pad 24 polishes the front surface of the semiconductor wafer 10. The surface of the semiconductor wafer 10 becomes globally planar after the chemical mechanical polishing process, as shown in FIG. 5.

Generally speaking, the polishing pads used in CMP of metal wire comprise hard (for example: IC-1000) and soft (for example: POLITEX) polishing pads. The former provides fast removal rate and great planarization effect, but the scratch problems isoccured. The latter can prevent scratch problems and provide a fine polishing effect and good cleaning performance, but the dishing problem of aluminum wire is induced. Therefore, in the prior CMP hard polishing pad is first used to polish the surface of the semiconductor wafer and then a soft polishing pad is used for further polishing so as to complete the planarization process. Two polishing processes are necessary to performed respectively, so both high time cost and consumption cost of polishing pads are required incurred resulting in a low efficiency of in the CMP.

SUMMARY OF INVENTION

It is therefore a primary objective of the present invention to provide a method of fabricating composite polishing pads used in chemical-mechanical process to solve the above-mentioned problems.

The present invention provides a method of fabricating a composite polishing pad. The method first provides a first polishing pad comprising a glue layer on a surface of the first polishing pad and a plurality of hard polishing materials positioned on the glue layer. Then portions of the first polishing pad are punched off to remove portions of the hard polishing material positioned on the surface of the first polishing pad so as to form a plurality of holes penetrating the first polishing pad. Thereafter, a second polishing pad comprising a glue layer on a surface of the second polishing pad is provided, and a plurality of soft polishing materials adhere to the glue layer. Then portions of the soft polishing material positioned on the surface of the second polishing pad are removed while retaining the glue layer, and the soft polishing material retained on the surface of the second polishing pad completely matches the holes formed in the first polishing pad. Finally, the first polishing pad is stuck on the surface of the second polishing pad so as to form a composite polishing pad comprising a pattern formed by the hard and soft polishing materials on the surface of the composite polishing pad.

The polishing pad fabricated by the present invention comprises a pattern formed by the hard and soft polishing materials on the surface of the polishing pad, so the composite polishing pad simultaneously providesa good removal rate and a great polishing effect. Only one polishing process is required to complete the planarization process, so the time and cost of the chemical-mechanical process is reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional diagram of a semiconductor wafer according to the prior art.

FIG. 2 is a perspective view of a chemical mechanical polishing apparatus according to the prior art.

FIG. 3 is a top view of a polishing pad according to the prior art.

FIG. 4 is a cross-sectional diagram of the polishing pad of FIG. 3.

FIG. 5 is a cross-sectional diagram of a semiconductor wafer after a chemical mechanical polishing process.

FIG. 6 to FIG. 10 are schematic diagrams of a method of fabricating the composite polishing pad according to the present invention.

FIG. 11 to FIG. 13 are top views of the second, third and forth embodiments of composite polishing pads according to the present invention.

DETAILED DESCRIPTION

Please refer to FIG. 6 to FIG. 10 of schematic diagrams of a method for fabricating the composite polishing pad according to the present invention. As shown in FIG. 6, the present invention provides a first polishing pad 40 that comprises a glue layer 42 on a surface of the first polishing pad 40 and a plurality of hard polishing materials 44 positioned on the glue layer 42. Then as shown in FIG. 7, portions of the first polishing pad 40 are punched off to remove portions of the hard polishing material 44 positioned on the surface of the first polishing pad 40 so as to form a plurality of holes 46 penetrating the first polishing pad 40.

As shown in FIG. 8, a second polishing pad 48 is provided that comprises a glue layer 42 on a surface of the second polishing pad 48 and a plurality of soft polishing materials 50 adhering to the glue layer 42. Thereafter, as shown in FIG. 9, portions of the soft polishing materials 50 positioned on the surface of the second polishing pad 48 is removed while the glue layer 42 is retained. The soft polishing material 50 retained on the surface of the second polishing pad 48 completely match the holes 46 formed in the first polishing pad 40.

Finally, as shown in FIG. 10, the first polishing pad 40 is stuck on the surface of the second polishing pad 48 so as to form a composite polishing pad 52. According to the present invention to complete the above-mentioned process, the surface of the composite polishing pad 52 comprises a pattern formed by interlacing the hard 44 and soft 50 polishing materials along an X-axis and Y-axis of the surface of the composite polishing pad 52. Hence the composite polishing pad 52 provides both a great removal rate and a good polishing effect.

Please refer to FIG. 11 to FIG. 13 of top views of the second, third and forth embodiments of composite polishing pad according to the present invention. As shown in FIG. 11, the surface of the composite polishing pad 54 comprises a pattern formed by arranging hard 56 and soft 58 polishing materials in concentric circles with different radiuses on the surface of the composite polishing pad 54. As shown in FIG. 12, the surface of the composite polishing pad 60 comprises a pattern formed by respectively arranging hard 62 and soft 64 polishing materials as rings in concentric circles with different radiuses on the surface of the composite polishing pad 60. As shown in FIG. 13, the surface of the composite polishing pad 66 comprises a pattern formed by interlacing hard 68 and soft 70 polishing materials along radial directions on the surface of the composite polishing pad 66.

The composite polishing pad fabricated by the present invention, as shown in FIG. 10 to FIG. 14, which comprises both hard and soft polishing materials on the surface of the composite polishing pad. The area ratio of hard and soft polishing materials positioned on the surface of the composite polishing pad is used to adjust removal rate and improve the uniformity of the surface of a semiconductor wafer after being polished so as to improve the throughput. The complete composite polishing pad is set in a chemical mechanical polishing apparatus and the chemical mechanical polishing apparatus further comprises a conditioner to control a distribution of a slurry on the surface of the polishing pad and to remove polished material that is formed during the polishing process.

In contrast to the prior chemical-mechanical process, which performs an initial polishing process by hard polishing materials followed by using soft polishing materials for further polishing and completing the planarization process, the composite polishing pad fabricated by the present invention comprises a pattern formed by the hard and soft polishing materials on the surface of the composite polishing pad. The composite polishing pad provides both great removal rate and good polishing effect. Only one polishing process is required to complete the planarization process, so both the time and cost of the chemical-mechanical process are reduced.

Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.

Patent Citations
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US3507739 *Dec 5, 1966Apr 21, 1970Ja Bar Silicone CorpPlaten
US4274232 *Jul 7, 1978Jun 23, 1981Minnesota Mining And Manufacturing CompanyFriction grip pad
US5609517 *Nov 20, 1995Mar 11, 1997International Business Machines CorporationComposite polishing pad
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7070480 *Oct 10, 2002Jul 4, 2006Applied Materials, Inc.Method and apparatus for polishing substrates
US9067297Nov 29, 2011Jun 30, 2015Nexplanar CorporationPolishing pad with foundation layer and polishing surface layer
US9067298Nov 29, 2011Jun 30, 2015Nexplanar CorporationPolishing pad with grooved foundation layer and polishing surface layer
US9296085Oct 31, 2014Mar 29, 2016Nexplanar CorporationPolishing pad with homogeneous body having discrete protrusions thereon
US20030114084 *Oct 10, 2002Jun 19, 2003Yongsik MoonMethod and apparatus for polishing substrates
US20050153633 *Feb 7, 2003Jul 14, 2005Shunichi ShibukiPolishing pad, polishing apparatus, and polishing method
US20070117393 *Nov 21, 2005May 24, 2007Alexander TregubHardened porous polymer chemical mechanical polishing (CMP) pad
US20070190911 *Mar 20, 2007Aug 16, 2007Sony CorporationPolishing pad and forming method
US20100216378 *Aug 26, 2010Jaekwang ChoiChemical mechanical polishing apparatus
US20120302148 *Nov 29, 2012Rajeev BajajPolishing pad with homogeneous body having discrete protrusions thereon
Classifications
U.S. Classification156/252, 451/529, 156/257, 156/293, 156/268, 451/526, 156/263, 451/528, 15/209.1, 451/533
International ClassificationB24B37/24, B24B37/26, B24D13/14
Cooperative ClassificationY10T156/1056, Y10T156/1082, Y10T156/1074, Y10T156/1064, B24B37/26, B24B37/24
European ClassificationB24B37/26, B24B37/24
Legal Events
DateCodeEventDescription
Jul 26, 2001ASAssignment
Owner name: UNITED MICROELECTRONICS CORP., TAIWAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HSUEH-CHUNG CHEN;TENG-CHUN TSAI;REEL/FRAME:011781/0312;SIGNING DATES FROM 20010622 TO 20010703
Sep 26, 2006FPAYFee payment
Year of fee payment: 4
Sep 26, 2010FPAYFee payment
Year of fee payment: 8
Sep 29, 2014FPAYFee payment
Year of fee payment: 12